Ethanol scare-mongering

Tell the Brazilians that ethanol causes engine damage. They've been using ethanol fuels for years and many of their cars can run on pure ethanol.

Car technology now makes it possible for flex-fuel engines to run on petrol or ethanol or any mix of the two - the engine automatically adjusts the tuning to suit.

In the US, E10 is widely used because it helps improve fuel combustion and reduces emissions. Americans' Toyotas, Mitsubishis and Nissans have run for years on E10 without problems.

What's the risk?

The main case against ethanol blends is a Japanese study released by New Zealand's Motor Industry Association. This indicates that using more than 3 percent ethanol in petrol might cause corrosion damage in fuel systems.

The Energy Efficiency Conservation Authority (EECA) disputes this. It says the study used an artificially corrosive blend of fuel - the researchers added peroxide and used a blend without corrosion inhibitor. Adding corrosion inhibitor to E10 is common industry practice and will be mandatory in all fuels sold here that receive the EECA biofuel label.

Corrosion can happen in cars that run on petrol; the oil industry has used corrosion inhibitor in petrol for many years to minimise this. Gull adds a little extra inhibitor to its E10 blend just to be sure.

Gull says it's had only praise and no complaints about the E10 blend, and is rapidly converting its service stations. (Sorry, South Islanders - Gull has no plans to bring E10 to you.)

The government will shortly begin tests to show that used Japanese imports can run on blends of 5 to 10 percent ethanol (as long as corrosion inhibitor is also used). Five percent ethanol is the minimum level of ethanol that oil companies want to introduce.

What about biodiesel?

Biodiesel blends with up to 5 percent biodiesel are likely to meet less resistance from the motor industry - provided they're made to the Petroleum Products Specifications Regulations and qualify for the biofuels label (see What is biofuel?).

Biodiesel that doesn't have the biofuels label may be a problem for more sophisticated modern engines - and using non-label biodiesel or blends above 5 percent biodiesel will most probably invalidate your warranty. So check with your dealer first.

Fuels that meet the biofuels-label rules have to perform as well in very cold temperatures as ordinary diesel.